FIGURE 1 

Experimental results reveal discrepancy between protein degradation dynamics at the single-cells and population level. (A, C) Time-course measurements of protein degradation for individual cells. The kinetics is zeroth-order for LAA-tagged GFP (A) and is first-order for ASV-tagged GFP (C). These data are representative of more than four independent experiments. Insets: when plotted on the semi-log scale, the single-cell degradation dynamics is curved for LAA, because it is zeroth-order, whereas the dynamics is linear for ASV. (B, D) The bulk degradation kinetics measured by fluorescence plate reader. The kinetics measured in bulk () is first-order for both LAA and ASV. The error bar represents average of four samples. The solid line is an exponential fit of the data. The kinetics of one of the single-cell measurements is also plotted for comparison (). The data are normalized against the initial time point to facilitate comparison. Insets: when plotted on the semi-log scale, the bulk degradation kinetics is close to linear (first-order), whereas the single-cell dynamics is curved (zero-order) for LAA only.